feat: Specify component types in detailed deps page

With the advent of multiple sublibraries per
package, it has become less clear what each
component is, on the 'detailed dependencies'
page.

This changeset replaces the tabulated view of

| component name | list of dependencies |
| -------------- | -------------------- |
| - lib 1        | - dep 1              |
|                | - dep 2              |
|                |                      |
| - exe 1        | - dep 3              |

With the more heirarchical:

Libraries
  - lib 1
    - dep 1
    - dep 2
  ...

Executables
  - exe 1
    - dep 3

This change is related to haskell#1218

src/Distribution/Server/Features/Html.hs

@@ -1461,7 +1461,7 @@ mkHtmlCandidates ServerEnv{..} utilities@HtmlUtilities{..}
 dependenciesPage :: Bool -> PackageRender -> URL -> Resource.XHtml
 dependenciesPage isCandidate render docURL =
     Resource.XHtml $ hackagePage (pkg ++ ": dependencies") $
-      [h2 << heading, Pages.renderDetailedDependencies render]
+      [h1 << heading, Pages.renderDetailedDependencies render]
        ++ Pages.renderPackageFlags render docURL
   where
     pkg = display $ rendPkgId render

src/Distribution/Server/Packages/Render.hs

@@ -67,10 +67,11 @@ data ModSigIndex = ModSigIndex {
 data PackageRender = PackageRender {
     rendPkgId        :: PackageIdentifier,
     rendLibName      :: LibraryName -> String,
+    rendComponentName :: ComponentName -> String,
     rendDepends      :: [Dependency],
     rendExecNames    :: [String],
     rendLibraryDeps  :: [(LibraryName, DependencyTree)],
-    rendExecutableDeps :: [(String, DependencyTree)],
+    rendExecutableDeps :: [(ComponentName, DependencyTree)],
     rendLicenseName  :: String,
     rendLicenseFiles :: [FilePath],
     rendMaintainer   :: Maybe String,
@@ -100,8 +101,9 @@ doPackageRender users info = PackageRender
     { rendPkgId        = packageId'
     , rendDepends      = flatDependencies genDesc
     , rendLibName      = renderLibName
+    , rendComponentName = renderComponentName
     , rendExecNames    = map (unUnqualComponentName . exeName) (executables flatDesc)
-    , rendExecutableDeps = (unUnqualComponentName *** depTree buildInfo)
+    , rendExecutableDeps = (CExeName *** depTree buildInfo)
                                 `map` condExecutables genDesc
     , rendLibraryDeps = second (depTree libBuildInfo) <$> allCondLibs genDesc
     , rendLicenseName  = prettyShow (license desc) -- maybe make this a bit more human-readable
@@ -182,6 +184,10 @@ doPackageRender users info = PackageRender
     renderLibName (LSubLibName name) =
       packageName' ++ ":" ++ unUnqualComponentName name
 
+    renderComponentName :: ComponentName -> String
+    renderComponentName (CLibName name) = renderLibName name
+    renderComponentName name@(CNotLibName _) = componentNameRaw name
+
 allCondLibs :: GenericPackageDescription -> [(LibraryName, CondTree ConfVar [Dependency] Library)]
 allCondLibs desc = maybeToList ((LMainLibName,) <$> condLibrary desc)
   ++ (first LSubLibName <$> condSubLibraries desc)

src/Distribution/Server/Pages/Package.hs

@@ -37,7 +37,7 @@ import qualified Text.XHtml.Strict
 import Data.Bool (bool)
 import Data.Maybe               (fromMaybe, isJust, mapMaybe, catMaybes)
 import Data.List                (intersperse, intercalate, partition)
-import Control.Arrow            (second, Arrow (..))
+import Control.Arrow            (Arrow (..))
 import System.FilePath.Posix    ((</>), (<.>))
 
 import qualified Documentation.Haddock.Markup as Haddock
@@ -201,11 +201,6 @@ moduleSection render mdocIndex docURL mPkgId quickNav = case renderedModules of
         renderedModules :: [(LibraryName, ModSigIndex)]
         renderedModules = rendModules render mdocIndex
 
-tabulate :: [(String, Html)] -> Html
-tabulate items = table ! [theclass "properties"] <<
-        [tr << [th << t, td << d] | (t, d) <- items]
-
-
 renderDependencies :: PackageRender -> (String, Html)
 renderDependencies render =
     ("Dependencies", summary +++ detailsLink)
@@ -236,12 +231,23 @@ nonbreakingSpan :: Html -> Html
 nonbreakingSpan str = thespan ! [thestyle "white-space: nowrap"] << str
 
 renderDetailedDependencies :: PackageRender -> Html
-renderDetailedDependencies pkgRender =
-    tabulate $ map (second (fromMaybe noDeps . render)) targets
+renderDetailedDependencies pkgRender
+  = mconcat (mapMaybe renderComponentType componentsByType)
+
   where
-    targets :: [(String, DependencyTree)]
-    targets = (first (rendLibName pkgRender) <$> rendLibraryDeps pkgRender)
-        ++ rendExecutableDeps pkgRender
+    componentsByType :: [(String, [(ComponentName, DependencyTree)])]
+    componentsByType =
+      [ ("Libraries", first CLibName <$> rendLibraryDeps pkgRender)
+      , ("Executables", rendExecutableDeps pkgRender)
+      ]
+
+    renderComponentType :: (String, [(ComponentName, DependencyTree)]) -> Maybe Html
+    renderComponentType (_, []) = Nothing
+    renderComponentType (componentType, items) = Just $ mconcat
+      [ h2 << componentType
+      , flip foldMap items $ \(componentName, deptree) ->
+        h3 << rendComponentName pkgRender componentName +++ fromMaybe noDeps (render deptree)
+      ]
 
     noDeps = list [toHtml "No dependencies"]
 
@@ -257,7 +263,7 @@ renderDetailedDependencies pkgRender =
                       NotBuildable -> [strong << "buildable:" +++ " False"]
 
     list :: [Html] -> Html
-    list items = thediv ! [identifier "detailed-dependencies"] << unordList items
+    list items = unordList items ! [identifier "detailed-dependencies"]
 
     renderComponent :: CondBranch ConfVar [Dependency] IsBuildable
                     -> Maybe Html